3 Answers
3

You need a so called profiler to measure which part of your application does make use of CPU and Memory Resources. XDebug is such a profiler for example. Using it will show you exactly which part of your application uses how much of CPU and memory.

It is extremely difficult / impossible to get the data on CPU usage on different plugins. They are after all just php functions. But because functions get called all over the place when a page is generated it's hard to see what's using how much.

What you could do is to measure all of php. You could try to disable/ enable plugins. This will give you an indication. But CPU usage can very much depending on content, users etc.